Some sonar systems employ sonar elements towed by a ship. So-called passive towed sonar systems typically have a towed line array of acoustic receiving elements. The passive towed sonar systems can passively receive sounds radiated by targets, for example, ships or submarines. Typically, the passive towed sonar system has processing capabilities that can, from the received sounds, detect the target, that can localize the target, and that can classify the target.
So-called active towed sonar systems typically have both a towed line array of acoustic receiving elements and also a towed sound source. The active towed sonar systems can generate acoustic pulses with the towed sound source. The sound pulses travel through the water, and impinge upon an object, for example, a ship, submarine, or a mine, creating echoes therefrom. The towed line array of acoustic receiving elements used in the active towed sonar system can receive the echoes from the targets. Typically, the active towed sonar system has processing electronics that can, from the received echoes, detect the target, that can localize the target, and that can classify the target.
Conventional towed active sonar systems us a first winch and a first associated tow cable to tow the line array of acoustic receiving elements and a second winch and a second associated tow cable to tow the towed sound source. Having two winches and two tow cables tends to result in excessive use of ship deck space and also complex deployment techniques.
Furthermore, conventional active towed sonar systems employ acoustic sound sources that tend to project sound omnidirectionally, i.e., in all directions. Thus, the conventional active towed sonar systems can interfere with other active towed sonar systems, or with any type of sonar systems, operating in proximity.
Still further, the conventional active towed sonar systems are unable to be towed at high speeds, particularly at high speeds that would enable the ship towing the active towed sonar system to move rapidly to a new location.
It would be desirable to provide an active towed sonar system that uses less deck space, that has an easier deployment technique, and that can have no loss of detection, localization, and classification of targets. It would also be desirable to provide an active towed sonar system that can operate in proximity to other sonar systems without causing interference into the other sonar systems. It would also be desirable to provide an active towed sonar system that can be towed at high speeds.